Forum Schedule Spring 2023

I will present our recent research on GRBs that deviate from standard GRB classifications or progenitor models. Those GRBs include the discoveries of a peculiar GRB from a magnetar giant flare, a genuinely short GRB not originating from a compact star merger, and a genuinely long GRB from a compact binary star merger. Those novel phenomena suggest that our understanding of GRBs is still far from complete, and a thorough investigation of those special events is needed to comprehend the diverse mechanisms of GRBs.

Special Relativity (SR) was developed in 1905 by Albert Einstein as a kinematic theory that compared measurements made in two inertial reference frames moving with respect to one another. In the usual presentation of SR, local observers note the time and position of events that happen in their immediate vicinity. Those individual observations are sent to a Command Center. The people in the Command Center collate and analyze the data to construct an overall picture of what is happening in spacetime. Their analysis implies that moving meter sticks shrink and moving clocks run slow. This talk aims to test the validity of those conclusions.

Webex meeting link:

https://unlv.webex.com/unlv/j.php?MTID=md47916dfa980c975156d142f22738980

meeting number:

2623 639 2807

password:

cWX3QaQi9$8

In the first 7 years of operation, ground-based gravitational-wave detectors LIGO and Virgo have detected nearly 100 compact binaries, most of them black hole binaries. In this talk I will describe what can be learned about the formation channels of black holes using the gravitational waves they emit, and what was actually learned with the current dataset. I will highlight "expected" results, surprising findings, and associated caveats. I will then describe the scientific potential of next-generation gravitational-wave detectors, which could be online in the 2030s. Whereas current observatories will detect at most hundreds of compact binaries, at redshift below ~2, next-generation detectors will discover hundreds of thousands of compact binaries per year, at redshifts as high as ~100. They will thus explore the high-redshift universe and the formation of the first stars and the black holes they left behind in a totally new way, and search for stellar-mass primordial black holes early in the history of the universe.

Over the past decades, observations of the cosmic microwave background (CMB) have established the standard cosmological model. In the future, 21cm signals from neutral hydrogen have great potential for cosmological and astrophysical studies. In this talk, I will briefly review the previous CMB observations. Then I will discuss the instrumentation and on-sky calibration of the Cosmology Large Angular Scale Surveyor (CLASS) and the Simons Observatory (SO). At the end, I will discuss how we can use the 21cm observation as a powerful probe to study cosmology,and introduce our novel mapping method for 21cm interferometric data.